title: Pharmacodynamics of alfaxalone after single-dose intramuscular administration in red-eared sliders (Trachemys scripta elegans): a comparison of two different doses at two different ambient temperatures.
abstract: OBJECTIVE
  This study compares the pharmacodynamics of two different doses of alfaxalone administered intramuscularly (IM) to red-eared sliders at two ambient temperatures.
  
  
  METHODS
  Prospective blinded crossover experimental study.
  
  
  METHODS
  Nine adult female sliders (Trachemys scripta elegans).
  
  
  METHODS
  Following a 2-week acclimation at 22-25 °C, nine sliders were randomly assigned to receive alfaxalone, 10 mg kg(-1) (W10), or 20 mg kg(-1) (W20) IM. Each turtle received each dose, with a minimum 7-day washout period. A blinded observer evaluated heart rate (HR), palpebral and corneal reflexes, muscle relaxation, handling, and response to toe pinch at the following points: pre-injection, and 5, 12, 20, 30, 45, 60, and 120 minutes post-injection. Turtles then acclimated to 18-20 °C for 63 days, and the experiment was repeated in this lower-temperature environment, with treatment groups C10 (alfaxalone 10 mg kg(-1)) and C20 (alfaxalone 20 mg kg(-1)) subjected to the same crossover design.
  
  
  RESULTS
  C10 and C20 groups had significantly lower intraanesthetic HR than W10 or W20, respectively. C10 and W20 were significantly more relaxed and easier to handle than W10. No significant differences were observed in palpebral reflex, nor responsiveness to the toe pinch stimulus. None of the turtles lost corneal reflex. W20 and C20 had prolonged recoveries, compared to low-dose groups within the same temperature environment. Recovery was also longer at C20 and C10 compared to W10.
  
  
  CONCLUSIONS
  Turtles given 10 mg kg(-1) were more relaxed and easier to handle in cold than warm conditions. Warm turtles were more relaxed and easier to handle when given 20 mg kg(-1) than those given 10 mg kg(-1). Cold conditions correlated with lower HR and longer recovery time for each dose category.
  
  
  CONCLUSIONS
  The turtles had dose-dependent and inconsistent responses to alfaxalone. Lower ambient temperature augmented the behavioral effects of this drug.
authors.affiliation: Department of Small Animal Medicine and Surgery, College of Veterinary Medicine, University of Georgia, Athens, GA, USA.
authors.forename: Molly K
authors.initials: MK
authors.lastname: Shepard
authors.forename: Stephen
authors.initials: S
authors.lastname: Divers
authors.forename: Christina
authors.initials: C
authors.lastname: Braun
authors.forename: Erik H
authors.initials: EH
authors.lastname: Hofmeister
mesh_terms: D000758:Anesthesia / Q000379:methods / Q000662:veterinary*; D000777:Anesthetics / Q000008:administration & dosage* / Q000494:pharmacology; D000818:Animals; D001767:Blinking / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D007273:Injections, Intramuscular; D009126:Muscle Relaxation / Q000187:drug effects; D059225:Nociception / Q000187:drug effects; D011277:Pregnanediones / Q000008:administration & dosage* / Q000494:pharmacology; D013696:Temperature; D014426:Turtles
chemical_list: D000777:Anesthetics; D011277:Pregnanediones; C006477:alphaxalone
keywords: Trachemys scripta elegans; alfaxalone; anesthesia; pharmacodynamics; reptile; turtle